I am not sure what the problem here is but just want to make sure you realize that if you were to do that, all the requests won’t be directly going to your home server, but they will be routed via your VPS. So the performance will be hit by quite a bit, depending on the ping to the VPS and the VPS upload and download speeds. It’s a very privacy focused approach and you probably don’t need that.
The only benefits you get are that if you browse the web and someone gets your IP, you won’t be able to be matched with your domain’s IP, and that the feds won’t be able to match your public services with your home network (and you in the result).
Otherwise you shall be good just making sure that the ports you expose on your router are the Nginx ones, and won’t experience increased latency on all your requests this way.
Are the ports on your home firewall open? You need to use the public IP of your home router, open the required ports on the router (you can limit them to accept the incoming request from your VPS IP), and map them to a specific local device IP address and port on your router